Multiple stage cementing



Patented Apr. 25, 1939 UNITED STATES PATENT OFFICE MULTIPLE STAGECEMENTING Duncan, Okla.

Application January 23, 1937, Serial No. 122,012

6 Claims.

This invention relates to the cementing of oil wells or the like, andmore particularly to an arrangement for cementing long strings of casingor pipe in stages so that all the cement which fills the annular spacesurrounding the casing may be supplied thereto without passing aroundthe bottom of the casing.

The multiple stage cementing of wells is now well known to those skilledin the art. A method and apparatus for accomplishing this is fullydisclosed in the U. S. patent to Halliburton, No. 1,860,669, granted May31, 1932, and in the reissue thereof, No. 19,570, reissued May 14, 1935.

In the multi-stage cementing of wells a valve structure, usually calleda multi-stage unit, is made up with the casing. The arrangement is suchthat at the proper time the valve in this unit is opened so that cementcan flow outwardly therethrough to the annular space surrounding thecasing. The valve may be a sleeve valve, as taught in the patentsmentioned above, and may be opened by one of the cementing plugs used inthe multiple stage cementing operation.

As taught in the above mentioned patents, a multiple stage cementingoperation may employ several plugs. Thus, for example, in theillustration of Figs. 9 and of the Reissued Patent No. 19,570, two plugstravel through the multi-stage unit without afiecting it, a third plugenters the multi-stage unit and opens the valve and a fourth plugfollows the upper slug of cement, this being the cement which flowsthrough the multi-stage unit.

After the cement has passed through the multistage unit some meansshould be provided for preventing thatv cement from flowing back intothe casing. The Reissued Patent 19,570 discloses spring-pressed valve 31on the multi-stage unit for this purpose.

It is an object of the present invention to provide a sleeve valvearrangement for preventing cement from flowing back into the casingafter it has passed outwardly through the multi-stage tuiit incorporatedtherein.

It is another object of the invention to provide a multi-stage cementingunit in which valve means will be opened and then closed by action ofthe cementing plugs used in the cementing operation.

It is a further object of the invention to provide a novel method ofmulti-stage cementing in which the plugs used in the operation actuatemeans which opens and then closes valves in the multi-stage unit.

Other objects and advantages reside in certain novel features of thearrangement and method, as will be more apparent from the followingdescription taken in connection with the accompanying drawing, in which:

Fig. 1 is a vertical cross-sectional view of the casing of an oil wellwith a multiple stage unit constructed in accordance with the presentinvention incorporated therein and showing the parts in their relativeposition as they are lowered into the well.

Fig. 2 is a vertical cross-sectional view of the arrangement of Fig. 1,but illustrating the relative position of the parts during the time thatcement is flowing outwardly through the multiple stage unit; and

Fig. 3 is a vertical cross-sectional view of the same apparatus as thatshown in Fig. 1, but showing the parts in their final position after thecement has been placed around the casing through the multiple stageunit.

The various parts in the drawing are shown with certain elementsexaggerated in size for the purpose of better illustrating theprinciples of the invention, but it will be understood'by those skilledin the art that the various parts will be of the proper size to bear thestrain for which they are designed and yet not occupy any more spacethan is necessary. 4

Referring to the drawing in detail, it will be seen that a multiplestage unit is there shown as consisting essentially of a collar orcasing member ll within which a sleeve i2 is positioned for longitudinalmovement therethrough.

The upper end of the member II is provided with screw threads l3 adaptedto receive and be secured to a stand or section of the casing ll whilethe lower end of the member II is provided with similar threads l5adapted to receive and support a lower section or stand of casing I 6.Thus the member H may be made up with the casing of the oil well.

The casing member II has a number of openings or ports l'lcircumferentially spaced therearound approximately midway between itsends. These ports are adapted to be opened and closed by movement of thesleeve l2 into successive positions.

Normally the sleeve l2 occupies the position shown in Fig. It is held inthis position by means of shear pins l8 welded or swaged to the casingmember II. In the arrangement illustrated in the drawing three pins iiiare used but it is obvious that their number and also their size may bevaried to make them have the requisite strength.

Located beneath the shear p ns I8 are a second set II which arepreferably somewhat larger than the pins I8 and also greater in number.In the arrangement of the drawing four shear pins 18 are employed.

The casing member II also is provided with latching means 28, theseconsisting merely of catch members mounted on leaf springs 2I secured onthe inside of the casing member II in recesses 22 as illustrated. Thesleeve I2 is provided with circumferentially spaced ports 23 which servethe double purpose of allowing fluid to fiow through the ports IT in themember I I when the ports i1 and 23 are in alignment and also as meansfor cooperating with the latch members 20 to hold the sleeve I2 in oneposition as will be explained further hereinafter.

The lower end of the sleeve I2 is provided with a valve seat or"doughnut ring" 24, as it is called in the trade, for cooperating withone of the cementing plugs to maintain a seal and cause the sleeve I2 tomove downwardly in its initial movement with respect to the casingmember II. The cementing plug which seats on the ring 24 is shown at 25in the drawing. This plug may be of known construction and consist of abody of wood having an aluminum or other metallic valve member 28mounted on its lower end and adapted to seat in the ring 24. The plugmay also be provided with one or more rubber cups 2'! for maintaining aseal between the plug and the casing.

The drawing also shows another plug 28 which may be similar to the plug25 except that it does not have a valve member on its bottom.

In cementing an oil well by means of the multiple stage process andusing the apparatus shown in the drawing, one slug of cement will bepumped to the bottom of the casing and there distributed in accordancewith known practices. If cementing plugs are used with this slug ofcement they will pass right through the multiple stage unit withoutmoving the sleeve l2 or otherwise altering the same. Since apparatus forthis purpose is well known it has not been shown herein.

The first slug of cement is followed by a body of mud or other fluid andthen the plug 28 is placed in the well and the second slug of cement ispumped in on top of this plug. The second slug of cement is followed bythe plug 28. As the second slug of cement and the plugs 28 and 28 arepumped downwardly through the well the first slug of cement is forcedoutwardly around the bottom of the casing. When the plug 25 reaches thering 24 it seats therein and the pressure of the pump at the surface israised suiiiciently to cause the pins I8 to shear. This causes thesleeve I2 to move downwardly to the position shown in Fig. 2, thusbringing the ports I1 and 23 into alignment and causing the second slugof cement to flow outwardly through the member II. The second set ofshear pins I! are designed to prevent the sleeve I2 moving downwardlyfurther at this time and are preferably of larger diameter than the pinsII and greater in number. However, there is but slight pressure exertedon the pins I 8 at this time due to the fact that as soon as the portsII are opened the fiuid pressure tending to move the sleeve I2downwardly is released, the cement flowing outwardly through the ports.The ports are preferably opened before the sleeve I2 reaches the pinsl8.

After all of the second slug of cement has flowed outwardly through thecasing II the plug 28 enters the sleeve I2 and rests upon the plug 28.The cups on the plug 28 maintain a seal with the sleeve I2. Upon raisingthe pressure at the pumps the second time the pins I! will shear andcause the sleeve l2 to move into the position shown in Fig. 3. This willclose the ports II by bringing the upper portion of the sleeve l2 intoalignment therewith. This will effectively seal the casing and preventthe flow of any cement back through the ports I1 into the casing.Additional sealing means may, of course, be provided by poppet valve onthe outside of the ports II in accordance with known practices.

The sleeve I2 is caught in its final position by the upper end of thestand of casing I6. To hold the sleeve I2 in this position the latchmembers 20 interlock with the ports 23 in the sleeve as shown in Fig. 3.It sometimes happens that changes in pressure within the casing tend tocause the sleeve to move upwardly, and to avoid the danger of the portsI! becoming accidentally opened agan the latch members 20 are provided.

The number of ports I1 and 23 may be varied in number and spacing inaccordance with the requirements but the arrangement is preferably suchthat some of the ports 23 will match up with some of the ports Il whenthe members are in the proper alignment longitudinally, irrespective ofrelative rotation. There should also be a sufiicient number of latchmembers 28 to insure at least one catching in a port 23 at the propertime.

While only one embodiment of the invention has been shown and describedherein, it is obvious that the arrangement may be modified in a varietyof ways and still accomplish the purposes set forth. The sleeve I2 maybe made of two parts, one of which is actuated to open the ports I1 andthe other of which is actuated to close the same, and the arrangementmay cooperate with the plugs in various ways to bring about the desiredaction. To facilitate drilling out the plugs 25 and 28 after thecementing operation is completed, it is preferable to provide some meansfor preventing the sleeve I2 from rotating with respect to the casingmember II but this has not been shown in the drawing because its use isobvious. One way of accomplishing this is to provide inter-engagingteeth on the bottom of sleeve I2 and the top of the section ii of thecasing. The latches 28 will ordinarily be sufilcient to prevent rotationas well as longitudinal movement of the sleeve, however. Various otherchanges may be made without departing from the spirit of theinvention orthe scope of the annexed claims.

we claim:

1. Apparatus for use in the multi-stage cementing of oil wells or thelike which includes a cylindrical member adapted to be made up with thecasing of the well, said member having ports therein, a sleeve withinsaid member, said sleeve having ports therein adapted to be. aligned inone position of the sleeve. with the ports in said member, releasablemeans cooperating with said member and sleeve to hold the ports thereofout of alignment, and releasable means cooperating with said member andsleeve to hold the ports in alignment.

2. Apparatus for use in the multi-stage cementing of oil wells or thelike which includes a cylindrical member adapted to be made up with thecasing of the well, said member having ports therein, a sleeve withinsaid member, said sleeve having ports therein adapted to be aligned, inone position of the sleeve, with the ports in said member, releasablemeans cooperating with said member and sleeve to hold the ports thereofout of alignment, and latching means for locking the member and sleevein such a relative position that the ports are out of alignment,

3. Apparatus for use in the multi-stage cementing of oil wells or thelike which includes a cylindrical member adapted to be made up with thecasing of the well, said member having ports therein, a sleeve withinsaid member, said sleeve having a portion provided with ports and aportion without ports on each side 01' said ported portion, and meanscooperating with said member and sleeve to hold the sleeve in relativepositions so that the ports of the member will be successively alignedwith an un-ported portion of the sleeve, then the ported portion andthen the un-ported portion.

4. Apparatus for use in the multi-stage cementing of oil wells or thelike which includes a cylindrical member adapted to be made up with thecasing of the well, a sleeve in said member and means for releasablyholding the sleeve in different positions with respect to the member,said sleeve having ports therein whereby the ports in the member may beclosed by the sleeve. then opened by movement 01' the sleeve to adifierent position to bring the ports in the sleeve in alignment withthe ports in the member and then again closed by the sleeve.

5. Apparatus for use in the multi-stage cementing of oil wells or thelike, including, in combination, a cylindrical member made up with thecasing of the well, said member having portstherein, a sleeve in saidmember adapted to open and close the ports in said member and aplurality oi cementing plugs, said sleeve having ports therein wherebyone of said plugs may engage the sleeve and cause the same to move tosuch position that the ports in the sleeve are in alignment with theports in the member to open said ports in said member and another orsaid plugs may cause the sleeve to move to another position to close theports in said member.

6. Apparatus for use in the multi-stage cementing of a casing in an oilwell including a sleeve valve adapted to be made up with the casing, aplurality of cementing plugs, means cooperating with one of said plugsto open the valve and means cooperating with another or said plugs toclose the valve positively and permanently.

WALLACE R. McCLENDON. WILLIAM D. OWBLEY.

